In recent years, in the manufacture of electronic devices, a method in which an application of ink containing a functional material is performed using an ink-jet head has been widely employed. The ink-jet head discharges ink to a printing target through minute nozzle holes provided in the nozzle plate.
With such an ink-jet head, part of discharged ink or foreign matters such as dust in the outside air may adhere to the nozzle surface of the nozzle plate. When such foreign matters adhere to the nozzle plate, appropriate discharging of ink is inhibited, and ink cannot be applied with high accuracy.
To solve this problem, printers provided with an ink-jet head typically have a wiping device that removes foreign matters adhered on the nozzle plate. One known wiping device employs a system in which a gas flow is applied to the nozzle surface of the nozzle plate to remove foreign matters.
In wiping devices that use a gas flow to remove foreign matters, gas is applied also to the inner part of the nozzle hole when gas is obliquely applied to the nozzle plate, and consequently, the ink inside the nozzle hole is dried, causing nozzle clogging.
Under such circumstances, some configurations have been proposed in which gas is ejected in parallel to the nozzle plate in order to remove foreign matters without causing nozzle clogging. However, in a configuration in which gas is ejected or sucked in parallel to the nozzle plate at a location below the nozzle plate, the flow velocity of gas decreases as the distance from the nozzle plate decreases, and thus a gas flow that can stably blow away the foreign matters cannot be easily obtained. In addition, a configuration may be conceivable in which part of the wiping device is brought into contract with the nozzle plate, and the gap between the nozzle surface of the nozzle plate and a surface of the wiping device is used as a gas path, whereby a gas having a high flow velocity is generated in parallel to the nozzle plate at a location directly below the nozzle plate. However, such a configuration causes a problem in which the contact wears away the water-repellent film of the nozzle plate.
Conventionally, in order to solve the above-mentioned problems, a wiping device has been proposed in which gas is guided along a curved surface by Coanda effect to generate a stable gas flow in parallel to the nozzle plate without contacting the nozzle plate (see, for example PTL 1). “Coanda effect” refers to a phenomenon in which, when an object is placed in a viscous fluid, the direction of the fluid is changed along the object.
FIG. 1 is an exploded perspective view of wiping device 210 disclosed in PTL 1, and FIG. 2 is a schematic view explanatory of a state where the wiping device of FIG. 1 wipes nozzle plate 11. FIG. 2 illustrates a cross-section taken along dashed line A0 of FIG. 1.
As illustrated in FIG. 2, in a wiping device utilizing Coanda effect, the gas ejected from gas jetting port 430 advances along a protruding curved surface of guiding section 410 so as to form a stable gas flow in parallel to nozzle plate 11. With this configuration, the foreign matters and ink drop 15 adhered on nozzle plate 11 are blown away, and sucked into gas suction port 450. In addition, since gas is not obliquely applied to nozzle plate 11 in a wiping device utilizing Coanda effect, the gas is not directed to the inner part of the nozzle hole, and therefore the nozzle hole is not clogged. Further, since such a wiping device does not make contact with nozzle plate 11, the water-repellent film on the surface of nozzle plate 11 is not worn away.